# CVE-2022-49021: linux: In the Linux kernel, the following vulnerability has been resolved:  net: phy: fix null-ptr-deref while probe() faile...

CVE-2022-49021 is fixed in linux on 1 platform, first by DEBIAN-CVE-2022-49021, released October 21, 2024. It is not reported as exploited. Patch Radar priority: Routine.

- Web page: https://patchblox.com/security/cve/CVE-2022-49021
- Priority: Routine
- CVSS: 5.5 (medium)
- EPSS: 0.0028
- CISA KEV: not listed
- Exploited (vendor report): no
- Publicly disclosed: no
- Published: Oct 21, 2024

## Description

In the Linux kernel, the following vulnerability has been resolved:  net: phy: fix null-ptr-deref while probe() failed  I got a null-ptr-deref report as following when doing fault injection test:  BUG: kernel NULL pointer dereference, address: 0000000000000058 Oops: 0000 [#1] PREEMPT SMP KASAN PTI CPU: 1 PID: 253 Comm: 507-spi-dm9051 Tainted: G    B            N 6.1.0-rc3+ Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.13.0-1ubuntu1.1 04/01/2014 RIP: 0010:klist_put+0x2d/0xd0 Call Trace:  <TASK>  klist_remove+0xf1/0x1c0  device_release_driver_internal+0x23e/0x2d0  bus_remove_device+0x1bd/0x240  device_del+0x357/0x770  phy_device_remove+0x11/0x30  mdiobus_unregister+0xa5/0x140  release_nodes+0x6a/0xa0  devres_release_all+0xf8/0x150  device_unbind_cleanup+0x19/0xd0  //probe path: phy_device_register()   device_add()  phy_connect   phy_attach_direct() //set device driver     probe() //it's failed, driver is not bound     device_bind_driver() // probe failed, it's not called  //remove path: phy_device_remove()   device_del()     device_release_driver_internal()       __device_release_driver() //dev->drv is not NULL         klist_remove() <- knode_driver is not added yet, cause null-ptr-deref  In phy_attach_direct(), after setting the 'dev->driver', probe() fails, device_bind_driver() is not called, so the knode_driver->n_klist is not set, then it causes null-ptr-deref in __device_release_driver() while deleting device. Fix this by setting dev->driver to NULL in the error path in phy_attach_direct().

## Where it's fixed

| Platform | Product | Fixed in | Fix | Released |
|---|---|---|---|---|
| Linux | linux Debian 12.15 (bookworm) | 6.0.12-1 | [DEBIAN-CVE-2022-49021](https://patchblox.com/security/data/fix/linux/debian-cve-2022-49021.md) | Oct 21, 2024 |
| Linux | linux Debian 13.5 (trixie) | 6.0.12-1 | [DEBIAN-CVE-2022-49021](https://patchblox.com/security/data/fix/linux/debian-cve-2022-49021.md) | Oct 21, 2024 |
| Linux | linux Debian 14 | 6.0.12-1 | [DEBIAN-CVE-2022-49021](https://patchblox.com/security/data/fix/linux/debian-cve-2022-49021.md) | Oct 21, 2024 |

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